RF identification technology is well known as a means of identifying persons or objects carrying radio tags over a short distance of typically 1 m or so, without physical contact. Applications of this technology include the tagging of animals, such as pet dogs, cattle and sheep, identifying the location of people in potentially hazardous areas, such as offshore drilling platforms, and the tracking of goods in retail and logistic situations. They form a basic mechanism for a very convenient form of interaction between a system and people or devices.
PCT Patent Specification WO97/06479 discloses a computerised interactor system which comprises means defining a detection space, a plurality of physical interactors which can be manually placed at desired positions within the detection space or removed from the detection space to provide a plurality of selectable and changeable arrangements of the interactors at the plurality of positions of the detection space. An interface responsive to an interactor is provided in the detection space and is operative to provide an interactor signal indicative of the identity and status of the interactor. A computer system is coupled to the interface and is operative to process the interactor signal to create a control input that is indicative of the identity and status of the interactor within a predetermined semantic framework. An application system is coupled to the computer system and is responsive to the control input. The disclosed interactor system depends on the spacial positioning of the interactors in the detection space in order to generate the interactive signal.